LONDON (Reuters) -U.S. energy officials are reassessing the risk posed by Chinese-made devices that play a critical role in renewable energy infrastructure after unexplained communication equipment was found inside some of them, two people familiar with the matter said. Power inverters, which are predominantly produced in China, are used throughout the world to connect solar panels and wind turbines to electricity grids. While inverters are built to allow remote access for updates and maintenance, the utility companies that use them typically install firewalls to prevent direct communication back to China.